The broad objective of the proposed program of research is to understand how chronic stress and the emotion regulation strategies of suppression and reappraisal affect emotional and physiological responses in naturalistic settings. More specifically, one study will examine the effects of perceived chronic stress, suppression and reappraisal on emotional experience and the cortisol awakening response in healthy undergraduates, who vary both in the use of these emotion regulation strategies and their perceptions of stress. The second study seeks to understand how suppression and reappraisal are associated with the cortisol awakening response in those who have endured repeated natural disasters (half of whom currently experience symptoms consistent with probable Posttraumatic Stress Disorder or PTSD). The specific aims of this particular program are threefold: 1) to establish the relationship between chronic stress, trait emotion regulation, emotional experience, and the cortisol awakening response in a healthy population (Study 1);2) to examine the link between trait emotion regulation and the cortisol awakening response in a natural setting among a chronically stressed population without PTSD (Study 2);and 3) to examine the relationship between the PTSD and CAR findings in a matched trauma-exposed sample, and clarify the relationship between trait emotion regulation and the cortisol awakening response in a natural setting among a chronically stressed population with PTSD( Study 2). Trait measures of emotion regulation, questionnaires on chronic stress, daily diary reports of emotion and health, and assessments of cortisol will be utilized to address the specific aims. In Study 1, healthy undergraduates will come into the lab to complete questionnaires on perceived chronic stress and the trait use of suppression and reappraisal. They will then complete a daily diary component where they will collect two saliva samples (one at awakening, one after 30 minutes) to measure the cortisol awakening response and will also complete an inventory on their current emotions each day. In Study 2, participants who have endured repeated natural disasters (e.g., earthquakes, tsunamis, floods), with and without probable PTSD, will be recruited from a larger study of coping with natural disasters. Half of the participants who meet criteria for probable PTSD will be matched on trauma exposure with participants who do not have PTSD. Participants will complete questionnaires on demographics, health, trauma exposure and the trait use of suppression and reappraisal. They will then complete a 1-day daily diary study similar to Study 1 to assess the cortisol awakening response. This project adheres to the mission of NIH because understanding how emotion regulation influences emotional experience and physiology in the context of chronic stress has implications for mental and physical health. Negative emotional responses occur frequently in reaction to chronic stressors;understanding which emotion regulation strategies may be better at alleviating these responses can be translated into intervention approaches. PUBLIC HEALTH RELEVANCE: This project has relevance to public health because it has the potential to a) shed light on the effects of emotion regulation on emotional experience and physiology in the context of chronic stress b) advance understanding on how specific emotion regulation strategies influence physiology in a healthy and chronically stressed population, and c) inform interventions by suggesting more adaptive emotion regulation processes to utilize when encountering chronic or repeated stressors. This is of great importance because those who suffer from chronic stress and poor emotion regulation are more prone to mental and physical health problems (e.g., clinical depression, coronary heart disease).